Experimental Investigation of Enhancement Heat Transfer by Natural Convection from Four Finned Cylinders in a Vertical Array Placed in a Conduit
Journal Title: International Journal of Mechanical and Production Engineering Research and Development (IJMPERD ) - Year 2019, Vol 9, Issue 5
Abstract
In this research, experiments have been implemented to enhance heat transfer by free convection from four finned cylinders that have helical fins, fixed horizontally inside conduit and using air as working fluid, the cylinders heated by electrical heaters at constant heat flux (188,341,573,832)W/m2 for Rayleigh number from (5ꓫ104 to 11.5ꓫ104 ) and Prandtl number (0.71)at the ambient temperature, approximately (24–26)oC and pressure at (1 atmosphere). The investigation include designed and manufactured test model, consist from two parts: moving and stationary, the stationary part is a frame made from iron that allows to move the part to inside it, according to ratio(H/D). The ratio (Y/D) changed four times (Y/D=2,4,6,8), the ratio (X/D) changed four times (X/D=1.5,3,5,7) and the ratio (H/D) changed four times (H/D=15,20,25,30). The results showed for all values of heat fluxes, the heat transfer coefficient and Nusselt number increases at separation distances (Y/D=4) & (X/D=3), which gives greater heat transfer rate, and any increasing or reducing lead to reduction in heat transfer rate. But regarding the ratio (H/D), the results showed there was no obvious influence or simple influence on heat transfer. Also, the results showed increased Nusselt number, with increasing Rayleigh number for all cylinders. The experiments have been implemented for single cylinder, placed in free air under constant heat flux, calculated (Nuo) and compared it with (Nui) for cylinders arranged in vertical array at the best case (Y/D=4) & (X/D=3) under the same heat flux (q ͌=341,573,832)W/m2 . The results show, there was obvious enhancement for the cylinders arranged in vertical array compared with singular cylinder in heat transfer, furthermore, this enhancement increases with increasing (Ra). From the results, empirical equation was found, to calculate the value of (Numean) that includes the two variables with (Ramean) as follows: Numean= 0.765Ra0.2 (Y/D) 0.08 (X/D) 0.01 (5ꓫ104≤ Ra ≤ 11.5ꓫ104).
Authors and Affiliations
Dr. Hassan K. Abdullah, Raad Y. Khudair
Keywords
Related Articles
- EP ID EP671647
- DOI 10.24247/ijmperdoct201920
- Views 98
- Downloads 0
An Optimisation of Spray and Performance Emission Characteristic of Biodiesel and its Blends by Varying Injection Timing in Diesel Engine
The main objective is to optimize the various parameters of spray for different blends of biodiesel and Injection pressure mainly with respect to Spray tip penetration Spray cone angle and Sauter Mean Diameter (SMD), usi...
Development and Study of Tribological Properties of Biocomposite for Brake Pad Application
Pollution is the adverse effect humanity has to suffer due to the technological advancement. Being engineers our objective is to design the machine elements based on sustainable, eco-friendly concepts. Due to wear in bra...
Energy, Exergy and Parametric Analysis of a New Cogeneration System Including the Brayton and Ammonia–Water Rankine Combined Cycle
Efficient consumption of energy resources and minimizing relevant costs are both substantial issues that not only don’t fade into insignificance by time but also have turned out to be essential concerns due to energy cri...
An Evaluation of Algae Biofuel as the Next Generation Alternative Fuel and its Effects on Engine Characteristics: A Review
Algae biofuels represent one of the most promising solutions to the current global energy crisis and climate change because of their potentially high yield, high production rate, biodegradability, non toxicity, carbon ne...
A Design of wide Band Antenna for Automotive Application
This paper proposes a wide band fix radio wire for vehicle correspondence. The plan prerequisites are to meet the frequencies of 3.5-5.5 GHz groups. The proposed reception apparatus comprises of a half circle fix implant...